Impact tool



' July 25, 1967 J. v. LOWERY 3,332,504

IMPACT TOOL Filed May 18, 1964 2 Sheets-Sheet 1 ATTORNEY J. V. LOWERY IMPACT TOOL July 25, 1967 2 Sheets-Sheet 2 Filed May 18, 1964' Mar/776: I 1 laws/y 30 i INVENTOR.

United States Patent 3,332,504 IMPACT TOOL James V. Lowery, 1225 N. Shepherd Drive, Houston, Tex. 77008 Filed May 18, 1964, Ser. No. 368,248 7 Claims. (Cl. 173-162) The present invention relates to new and useful improvements in impact tools and more particularly to a new and improved noise muffler and vibration dampener for fluid-actuated impact tools.

The present pneumatic or other fluid-actuated impact tools, particularly of the reciprocal percussion type, are objectionable because of the extreme noise and vibration produced by their use. The noise of a pneumatic hammer or chipper or the like is extremely annoying to the operator and those who work in the immediate vicinity of the tool and creates a disturbing nuisance to others in a large area around where the tool is being used. Also, because of the extreme vibration of the present pneumatic impact tools, their operation is greatly fatiguing, and in some instances injurious to the operator of the tool. Generally, one man can operate such a tool only intermittently and then for only short periods of time without being relieved.

It is therefore an object of the present invention to provide a new and improved impact tool which substantially eliminates the usual noise and vibration caused by the operation of prior impact tools. 7

Another object of the present invention is to provide a new and improved resilient mounting device for diminishing the shocks and vibrations caused by the operation of a fluid-actuated tool.

A further object of the present invention is to provide a new and improved impact tool which is much less fatiguing on the operator and which allows the tool to be operated for longer periods without interruption.

Another object of the present invention is to provide a new and improved impact tool wherein a fluid-actuated motor and its muflled exhaust conduits are resiliently mounted in a resilient material such as live rubber in a support housing or case.

And yet another object of the present invention is to provide a new and improved impact tool wherein a fluidactuated motor or power means reciprocates relative to its support housing and is suitably mounted thereon for reducing the vibration and noise usually produced by such impact tools.

And yet a further object of the present invention is to provide a new and improved impact tool wherein the power means and the working tool attached thereto are resiliently mounted between oppose-d springs in a support housing to reduce the amount of shock or vibration transmitted to the tool operator.

And still another object of the present invention is to provide a new and improved impact tool which is resiliently mounted in a support housing between tension loaded and compression loaded springs.

Another object of the present invention is to provide a new and improved impact tool wherein a working tool is formed integrally with a piston which is reciprocated in a fluid-actuated power means to eliminate the noise and vibration and the loss of power from a free piston strik ing a shaft to which the working tool is connected.

And yet another object of the present invention is to provide a new and improved impact tool having a shaft for mounting a working tool formed integrally with a reciprocating piston wherein such shaft is adapted to be inserted into the hole or opening formed by the working tool attached thereto.

And yet another object of the present invention is to provide a new and improved impact tool having a quick- 'ice release coupling lock on its working tool shaft to facilitate connecting and disconnecting a bit or working tool thereto.

And yet another object of the present invention is to provide a new and improved impact tool having a resilient skirt extending downwardly from its lower end for partially supporting the impact tool and for dampening the vibration produced-thereby.

And yet a further object of the present invention is to provide a new and improved impact tool which is resiliently mounted in a support housing and which has a resilient annular support member extending from its lower end for supporting and stabilizing the tool and also for reducing the vibration produced thereby.

And yet a further object of the present invention is to provide a new and improved impact tool having a baffled exhaust conduit and a resilient mounting in its support housing for reducing the noise and vibration of such tool.

And still another object of the present invention is to provide a new and improved fluid actuated power means having a fluid cushion formed at the end of each stroke of a reciprocating piston to prevent the piston from engaging the ends of the cylinder and having a baffled exhaust conduit to minimize the vibration and noise produced by the operation of the power means.

The preferred embodiment of this invention will be described hereinafter, together with other features thereof, and additional objects will become evident from such description.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and where- FIG. 1 is a view partly in elevation and partly in section showing the device of the present invention supported on a resilient skirt with the working tool extending into a hole formed therebelow;

FIG. 2 is a sectional view showing details of construction of the reciprocal piston motor and mufl ler of the present invention'with the piston near the forward end of its stroke;

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2 showing details of the fluid actuated power means of the present invention with the exhaust conduits shown in dotted lines;

FIG. 4 is a sectional view taken on line 4-4 of FIG. 2 showing details of one form of muffler 'baflle of the present invention;

FIG. 5 is a view partly in section and partly in elevation showing details of the quick release lock mechanism for connecting working tools to the piston'shafe of the present invention; and

FIG. 6 is a sectional view showing additional details of the fluid actuated power means of the present invention with the piston near the rearward end of its stroke.

In FIG. 1 of the drawings, the apparatus of the present invention is designated generally by the letter A. Briefly, the apparatus A comprises a support housing H in which a power means or motor P is resiliently mounted by means of opposed springs C and T, the purpose of which will be explained in detail hereinafter. Such motor P is adapted to directly reciprocate a working shaft S on which a hammer or chisel or other working tool or bit B may be connected. The motor P is fluid actuated, as will be explained, and has a series of mufllers 'M provided therein for diminishing the noise caused by its operation. A resilient annular skirt or spring foot R, which is adapted to extend from the front end of the motor P to the surface being worked on, cooperates with the suspension members C and T to substantially eliminate the vibration and noise caused by the operation of the impact tool A.

Considering now the apparatus of the present inventionin more detail, the support housing H preferably comprises a cylindrical case or body 11 which has a cap or cover 12 which is provided to close the upper or rear end of the body 11. Such cap or cover 12 may be formed integrally with the case 11 or may be secured thereto by welding or other suitable means, as desired. Such cap 12 normally has a pair of handles 13 provided on opposite sides thereof for manipulating the impact tool A of the present invention. Also, the cap 12 normally has a longitudinally extending recess or cavity 15 formed therein which is provided for receiving the spring C. As shown, the cavity 15 has an annular shoulder 16 formed adjacent thereto which is provided for engaging the rear end of the fluid actuated motor P to limit its longitudinal move ment in the case or body 11, and, normally, a cushion or buffer 16a formed of rubber or other suitable resilient material is provided on the annular shoulder 16 to cushion the impact of the motor P therewith.

The fluid-actuated power means P is preferably operated by compressed air, however, other gases or fluids may be used. Usually, a fluid supply conduit 20, which is provided for conducting the pressure fluid, such as compressed air, to operate the pneumatic motor P as will be explained, extends through one of the handles 13. A control valve 21 is normally provided in the conduit 20 and positioned in the handle 13 to allow the operator of the tool to manually control the flow of pressure fluid to operate the tool A.

As shown, an annular flange or a plurality of laterally extending projections 23 are provided for securing one end of each of the springs T to the case 11 for a purpose to be described hereinafte The motor P preferably comprises a cylindrical or tubular member 27 which is adapted to fit slidably within the cylindrical case 11. As shown (FIG. 2) the tube 27 has a head or end member 28 provided at its upper or rear end which preferably has a lug or projection 28a formed thereon for receiving one end of the spring C. The head 28, which is normally held in the tubular member 27 by means of the spring C or other suitable securing means, is provided for closing the upper end of the body 27 and for transmitting the thrust of the spring C to the motor P. Such head 28 also normally has an annular passage or channel 29 formed on the opposite side thereof from the projection 28a and a port or vent 30 formed therein for conducting fluid from the conduit 20 to the channel 29 for operating the pneumatic motor P as will be described herein. As shown, the head 28 also has a recess 28b formed therein which is provided for receiving the piston of the pneumatic motor P as will be described herein.

An annular flange or projection 25 is normally formed near the front or lower end of the tube 27 for securing an annular ring 26 thereto. Such ring 26 has holes or openings 26a formed therein which are normally aligned with similar holes or openings 23a in the opposed flange 23 and which are provided for receiving the opposite ends of the springs T from the ends connected in the openings 26a to connect the forward end of the tube 27 and the forward end of the case 11.

A resilient skirt, R formed of a helically coiled spring or other suitable resilient device, is normally provided at the forwardmost end of the tube 27. Such spring R preferably is inclined or tapered laterally outwardly from the forward end of the tube 27 to provide greater stability as well as support for the impact tool A. Such skirt R is adapted to support and stabilize the pneumatic tool as well as absorb a part of the shock caused by its operation whether the tool is used on a substantially smooth flat surface or whether it is employed on an inclined or uneven surface as indicated at 31 in FIG. 1 of the drawings.

Considering next the pneumatic motor P of the present invention, which is best seen in FIGS. 2 and 6 of the drawings, such motor P comprises a cylinder block 35, which is adapted to receive a piston 40, and a distributing valve assembly 50 that is provided for distributing a pressurized fluid, such as compressed air or the like, to reciprocate the piston 40, as will be explained hereinafter.

The piston 40 normally has a head or upper surface 41 which is formed at its upper or rear end for receiving pressurized fluid and a drive shaft or rod 43 which is normally formed integrally with such piston or connected thereto with suitable connecting means at its lower or forward end 45 to provide a unitary piston and shaft construction and thereby eliminate the power loss caused by a free piston striking or hammering on a shaft. As shown, such shaft 43 has a smaller diameter than the piston body 40. Usually, an annular inclined surface or shoulder 42, which is preferably inclined inwardly and downwardly from the piston 40 to theshaft 43 is provided at the lower end of such piston for a purpose to be explained hereinafter. The juncture 42a of the piston 40 and the piston shaft 43 preferably has a smooth rounded surface to relieve any stress in the piston or shaft and thereby decrease the likelihood of a separation occurring at such juncture.

The cylinder block 35 normally has a substantially cylindrical bore or chamber 36 for receiving the piston 40 and the counterbore 36 formed thereabove, or rearwardly of the bore 36, for receiving the distributing valve assembly 50, as will be explained.

The lower or forward end of the chamber 36 has a smaller diameter counterbore or passage 38 formed therein for receiving the shaft 43 which is formed at the lower end of the piston 40. An annular sleeve 39, which is formed of nylon or plastic or other suitable resilient material is preferably provided at the lower end of the chamber 36 to provide a tapered seat 37 for engagement by the similarly inclined shoulder 42 on the piston 40.

As shown in FIG. 2, the counterbore 38 is machined to provide a precise fit with the shaft to allow the shaft to reciprocate in the counterbore 38 with either substantially no air loss or with a minimum air loss there through. The piston cylinder block 35 also has a fluid passage or conduit 47 formed therein for conducing pressurized fluid to the lower end of the piston cylinder 36. Two or more ports 47a and 47b, respectively, are provided in the cylinder block 35 for conducting pressurized fluid to the lower end of the cylinder 36 to reciprocate the piston 40 rearwardly or upwardly in such chamber as will be described hereinafter.

As shown, the distributing valve assembly 50 comprises a hollow sliding spool type valve 51 which is adapted to be reciprocated in a valve chamber 61 for distributing the flow of pressurized fluid to the opposite ends of the piston chamber 36 to reciprocate the piston 40 therein.

Such spool type valve preferably comprises a tubular member 51 having a substantially cylindrical passage 52 extending longitudinally therethrough which is of substantially the same inside diameter as the piston cylinder 36 and which is adapted to receive the piston 40.

As shown, such valve body 51 has an annular shoulder 51a formed at its upper end and an annular groove 53 formed intermediate its upper end 51a and its lower end 51b. Such annular groove has a pair of opposed shoulders 53a and 53b formed therein with the shoulder 53a above the lower shoulder 53b. Also, the valve 51 has an annular rim or projection 54 formed thereon adjacent the lower side of the annular groove 53 so that the annular surface 53b forming the lower side of the groove 53 also forms the upper annular shoulder or surface on the projection 54. Such projection 54 also has a lower annular shoulder 54b formed thereon for a purpose to be described.

The valve chamber 61 has an upper end or portion 62 which is formed in an inlet valve block 71 and a lower portion 63 formed in an exhaust valve block 72. Such distributing valve blocks 71 and 72, respectively, are generally cylindrical in configuration and are adapted to be positioned in the counterbore 36' in the piston cylinder 'block 35. Normally, an upper piston cylinder portion 36a is formed up the upper portion of the valve block 71 above the'chamber 61 for receiving the piston 40 on its upward stroke.

The valve chamber 61 preferably comprises the central bore 61'with its upper and lower portions 62 and 63, respectively, and a pair of counterbores 62a and 63a, respectively. The counterbore 62a is provided intermediate the upper portion 62 and the lower portion 63 for receiving the annular projection 54, and the counterbore 63a is provided near the lower end 63 for a purpose to be described hereinafter.

The counterbore 62a has annular shoulders 62b and 620, respectively, formed therein. The annular shoulder 62b is provided at the upper end of the counterbore 62a for engaging the annular shoulder 53b of the projection 54 to limit the upward stroke of the sliding valve 51 as shown in FIG. 6 of the drawings. Similarly, the annular shoulder 630 is formed at the lower side of the counter bore 63a for receiving or engaging the annular shoulder 54b formed on the lower side of the annular projection 54 to limit the downward stroke of the sliding valve 51, as shown in FIG. 2 of the drawings.

It should be noted that the sliding valve 51 and the piston 40 are aligned coaxially with respect to each other so that each is free to move longitudinally relative to the other.

The cylindrical block 71 is normally provided with one or more upper fluid inlet passages 73 and 73a, respectively, and one or more fluid inlet passages 74 and 75, respectively. A pin or dowel 280 is provided for aligning the head 28 and the valve block 71. I

As shown, the fluid inlet passages 73 and 74 have their upper ends aligned so as to communicate with the annular fluid supply passage 29 formed in the head 28 whereby fluid introduced through the inlet port 30 may be communicated to such passages 73 and 74, respectively. The upper fluid inlet passage 73 is normally connected to the upper end of the valve chamber 62 for conducting fluid to the upper end of the piston chamber 36 to move the piston 40 downwardly when such passage 73 is opened by the valve 51. Similarly, the fluid inlet passage 73a is provided for communicating fluid pressure from the passage 73 to the upper annular shoulder 51a for moving the slidable valve 51 downwardly when the passage 73 is closed, as will be explained. However, it should be noted that the annular shoulder 51a does not normally engage the annular surface 61a when the valve 51 is at the upper end of its stroke (FIG. 2) and that communication through the passage 73a is always open to the upper portion 36a of the piston cylinder 36.

The lower fluid supply conduits 74 and 75, respectively, are adapted to be connected together by means of the annular groove 53 in the slidable valve 51 to conduct pressurized fluid to the lower or front end of the piston cylinder 36 for cushioning the downward or forward thrust of the piston 40 and also for urging such piston rearwardly relative to the cylinder 36.

The cylindrical block 72 normally has an annular shoulder 62c formed therein which is adapted to fit into the counterbore 62a formed in the cylindrical block 71 for aligning such cylindrical blocks 71 and 72, respectively, relative to each other. The block 72 normally has a passage 75a formed therein which is adapted to connect the lower fluid passage 75 formed in the cylindrical block 71 and the fluid passage 47 formed in the piston cylinder block 35 to form a continuous conduit for conducting pressurized fluid to the lower end of the piston cylinder 36. As best seen in FIG. 3, the cylindrical block 72 also has a plurality of exhaust passages 72a formed therein which is provided for exhausting pressurized fluid from the piston cylinder 36 to the exhaust mufiers M.

A passage 72b is formed in the cylindrical block 72 for communicating fluid pressure from the counterbore 63a to the counterbore 62a to move the slidable valve 51 upwardly from the lowermost end of its stroke, for a purpose to be explained. When the valve 51 is in its lowermost position as shown in FIG. 2 of the drawings, fluid pressure is communicated through the counterbore 63a to the passage 72b which conducts such fluid pressure to the lower annular shoulder 54b of the spool type valve 51.

An aligning pin or dowel pin 72c is preferably formed on the cylindrical block 72 and extends upwardly into the block 71 and downwardly into the piston cylinder housing 35 to align the passages 72a with their corresponding passages 350 formed in the piston cylinder block 35 and the passages 75, 75a and their corresponding passage 47.

As shown in the drawing, a circumferentially extending manifold or body 83 is provided in the case 27 for receiving exhaust fluid from the piston chamber 63.

One or more conduits 84 are provided above the manifold chamber 83 which are aligned with the exhaust passages 72a in the exhaust valve block 72 and which are connected to the manifold 83 for conducting exhaust fluid thereto. The exhaust manifold 83 is normally connected to one or more mufllers 85 by means of passages or conduits 86. One of such mufllers 85 is normally provided for each of the exhaust conduits 72a.

As best seen in FIG. 2 of the drawings each of the mufflers 85 is substantially cylindrical and includes a plurality of substantially semicircular baflie plates 87 which are spaced longitudinally relative to each other and which are positioned alternately on opposite sides of the mufller chamber 85 to form an undulating passage therethrough. As best seen in FIG. 4 of the drawings, each of the semicircular baflle plates 87 has a semicircular opening 87a formed concentrically thereof. Such semicircular openings 87a are aligned substantially axially of the cylindrical chambers 85 and are also aligned with the fluid passage 86 and with a fluid exhaust 88 formed at the opposite end of such chamber 85 from the fluid inlet 86. The semicircular openings 87a form a substantially circular bore or passage through each exhaust chamber 85. Each of the exhaust passages 88 normally has a flared port 89 formed at the forwardmost end thereof which is provided for discharging the exhaust fluid to the atmosphere.

A substantially unitary sleeve or body of resilient material such as rubber or other suitable material is provided in the case 27 surrounding the piston cylinder housing 35, the manifold 83 and the mufllers as well as the conduits 84, 86 and 88. Such resilient material 80 substantially fills the case or housing 27 to muffle sound from the pneumatic motor P as well as absorb the shocks and vibrations produced by operation of the tool.

As best seen in FIG. 5 of the drawings, a quick release lock mechanism 90 is provided for quickly and easily connecting or disconnecting a working tool B such as a hammer or a chisel or a bit, to the forwardmost end of the piston shaft 43. Such lock mechanism has a smaller diameter than the tool with which it is used and there fore the piston shaft 43 may be inserted into the hole or opening formed by the tool B.

The lock mechanism 90 comprises a pivotally mounted key 91 which is secured to the forward end of the piston shaft 43 by means of a pivot pin 92. Each cutting or chipping tool or hammer which is used with the device of the present invention is normally secured thereto by means of a threaded pin 90a or other releasable securing means. Each of such tools B normally has a substantially plane surface 93 formed adjacent the threaded pin or shaft 90a which is provided for securing the tool in the piston shaft 43. Such plane surface 93 is normally engaged by the forwardmost end 94 of the key 91 and is normally constantly urged thereagainst by means of a resilient spring 95 or other suitable means for urging the key 91 in contact with the plane surface 93. When it is desirable to replace the tool B, the resilient spring 95 may be manually depressed by urging the rearward portion of the key 91 laterally inwardly and thereby pivoting the forward portion of such key laterally outwardly to disengage the key 91 from the plane surface 93, thereby allowing the threaded connection 90a to be broken and the tool B to be removed.

Similarly, in connecting a tool or bit B to the forward end of the working shaft 43, the key 91 is pivoted so as to allow the tool to be threaded into the piston shaft 43. Thereafter the key 91 may be released allowing the spring 95 to urge the lower or forwardmost portion 94 into engagement with the plane surface 93 to lock such tool or bit B against rotation relative to the working shaft 43.

In operation, the apparatus of the present invention is normally connected to a pressurized fluid supply source such as an air compressor or the like by means of a conduit 20 which is connected to the inlet port 30 of the tool head 28. Such pressurized fluid is conducted through the annular passage or channel 29 in the head 28 into the pressurized fluid supply passages 73 and 74 respectively. When the piston 40 and the slidable valve member 51 are in the rearward or upward position as viewed in FIG. 6 of the drawings, the valve member 51 closes olf communication through the fluid inlet channel 73. However, communication is then open through the inlet passages 73a and 74. Fluid passing through the inlet passage 74 is conducted through the annular passage 53 formed on the slidabel valve 51 which spans the passages 74 and 75, respectively, to conduct fluid pressure through the passage 47 and the ports 47a and 47b, respectively, into the lower or forwardmost end of the piston cylinder 36.

It should be noted that when the valve 51 is in this position the annular shoulder 53a formed on the rearward side of the annular groove 53 and the exposed portion of the annular shoulder 53b, which is formed on the opposite or forward side of the groove or channel 53 have substantially the same surface area exposed to the pressurized fluid in such annular groove 53. Thus, when the slidable valve 51 is adjacent the upper or rearmost end of the chamber 61 the pressurized fluid passing from the chamber or passage 74 to the passage 75 exerts a substantially equal pressure in opposite directions on the slidable valve 51 and therefore the pressure in the groove 53 does not move it in either direction. However, the relief pipe or conduit 73a which is open to the upper piston cylinder chamber 36a provides a sufiicient pressure to the annular surface 51a of the slidable valve 51 and to the upper surface 41 of the piston 40, to move the valve 51 and the piston 40 longitudinally downwardly or forwardly in their respective chambers 61 and 36.

When such valve 51 begins to move forwardly the annular shoulders 62b and 53b, respectively, are disengaged and the surface of the shoulder 53b is exposed to the pressurized fluid conducted through the passage 74 into the annular groove 53.

As the slidable valve 51 moves forwardly or downwardly the fluid inlet passage 73 is opened or uncovered and additional quantities of pressurized fluid are supplied to the exposed upward or rearward surface 41 of the piston 40 and also to the annular shoulder 51a to further urge the piston 40 and the slidable valve 51 downwardly or forwardly. However, as such valve 51 uncovers or opens the passage 73, it also closes or covers the passage 74 to close off the supply of pressurized fluid to the lower end of the cylinder 36. When such slidable valve 51 reaches the forwardmost position in its stroke as shown in FIG. 2 of the drawings the annular shoulder 54b engages the opposite annular shoulder 620. When the valve 51 is in this position the passages 74 and 75 are both closed and communication is closed off through the exhaust port 72a.

The piston 40 with the shaft 43 disposed therebelow continues to be moved downwardly by fluid pressure conducted through passages 73 and 73a. However, with the upper or rear end 75 of the passage 47 closed, the pressurized fluid which was introduced into the lower or forward portion of the piston chamber 36 below the piston 40 cannot escape, and thus the downward or forward motion of the piston 40 and the piston shaft 43 are slowed by the compressed fluid which is entrapped below the piston 40 in the cylinder or chamber 36. Such trapped or compressed air or fluid forms a cushion in the cylinder 36 which prevents the piston shoulder 42 slapping or striking the tapered or annular shoulder 37 formed at the lower extremity of the cylinder chamber 36.

Before the piston 40 reaches the lowermost position in its stroke (FIG. 2), the slidable valve 51 is moved rearwardly or upwardly in the chamber 61 by the action of the pressurized fluid passing through the conduit 72b thereon to reopen the fluid supply passages 74 and 75, respectively, to inject additional pressurized fluid into the lower portion of the chamber 36 through the ports 47a and 47b to reverse the downward or forward motion of the piston 40 and to urge it upwardly or rearwardly in the cylinder 36 to the position shown in FIG. 6 of the drawings.

When the slidable valve 51 is moved forwardly to its forwardmost position as shown in FIG. 2 of the drawings, the counterbore 63a and the relief tube or pipe 72b connected thereto are not closed, thereby allowing the pressurized fluid in the piston cylinder 36 above the piston 40 to act upon the slidable valve 51 to move it rearwardly from its forwardmost position. It will be noticed that the exposed area of the upper annular surface 51a and the lower annular surface 51b are substantially the same. Thus, after the upper end 41 of the piston 40 moves forwardly beyond the lower end 51b of the valve 51, the fluid pressure on the shoulders 51a and 51b is substantially equalized. However, the pressurized fluid which is communicated through the relief tube 72b acts on the annular shoulder 54b to move the slidable valve 51 rearwardly in the chamber 61.

Such pressurized fluid passing through the passage 72b will move the slidable valve 51 back to its rearmost position as shown in FIG. 6 of the drawings where the valve will remain until the piston 40 has been returned to its rearmost position which is also shown in FIG. 6 of the drawing. Thereafter, the action of the pressurized fluid in troduced through the inlet passages 73 and 73a, respectively, will act to again urge the piston 40 and the slidable valve 51 to move downwardly as described herein.

With the slidable valve 51 in its rearmost position, the piston 40 is moved rearwardly by the action of the pressurized fluid introduced into the lower portion of the piston cylinder 36 through the ports 47a and 47b, respectively. As the piston 40 approaches the rearmost end of its stroke the pressurized fluid which is entrapped thereabove in the chamber 36a and cavity 28b is compressed to form a cushion to prevent the top or rearmost portion of the piston 41 from engaging the head 28 and thereby to prevent the vibration and noise as well as wear on the tool caused by the impact of the piston 40 with the head 28.

Thus, the piston 40 and the piston shaft 43 may be reciprocated in the fluid actuated motor P with the vibration and noise usually caused by impact tools substantially eliminated.

Each time the piston 40 moves rearwardly in the cylinder 36 from its forwardmost position therein as shown in FIG. 2 of the drawings, the slidable valve 51 is in its uppermost position as shown in FIG. 2 of the drawings. With the slidable valve 51 in this position the exhaust ports 720 are open and the pressurized fluid in the cylinder 36 below the piston 40 is then conducted through the conduit 72a to the exhaust chamber or manifold 83. Thereafter, such escaping fluid is conducted through the conduit 86 to the baffled mufiler chambers and then through the passage 88 to the atmosphere. As the stream of escaping pressurized fluid passes through the manifold chamber 83 and the baffled muffler chambers 85 it is directed through an undulating path and substantially broken up so that the noise and vibration which such stream of escaping fluid would normally cause is greatly diminished.

When such valve 51 is moved downwardly, the exhaust passages 7211 are closed (FIG. 2) and remain closed until after the upper end 41 of the piston 40 has passed below the lower shoulder 51b of the valve 51 and until the pressure in the chambers 63 and 630 are increased sufficiently to raise the valve 51. The fluid pressure from the chamber 63a is conducted through the passage 72b to raise the valve 51.

When such valve 51 is lifted or moved to its rearmost position (FIG. 6) the passages 72a are again opened and fluid in the valve chamber 61 and in the chamber 36 above the piston 40 exhausts through such passages 72a to the manifold 83 and thence through the mufilers 85 to the atmosphere as. explained herein.

When the piston 40 is raised in the chamber 36 sufficiently for the upper end 41 to enter the bore 52 in the valve 51, communication of fluid above the piston 40 in the valve chamber 61 is closed off to the exhaust passages 72a and such fluid is thereafter compressed above the piston 40 to form a fluid cushion between the rising piston 40 and the upper end 28 to prevent such piston from striking or engaging the member 28 as explained herein.

After the lower end 45 of the piston 40 passes above the upper end of the chamber 36 into the counterbore 63, fluid below such piston 40 is allowed to pass through the exhaust passages 72a to the atmosphere, as explained, as long as'the valve 51 is above the passages 72a. When such valve 51 is again moved forwardly or downwardly on the subsequent stroke, the exhaust port 72a is again closed. It can be appreciated that the valve 51 is repeatedly opened and closed to reciprocate the piston 40 and the piston shaft 43- as described herein.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims 'without departing from the spirit of the invention.

What is claimed is:

1. An impact tool comprising:

(a) a housing having a piston cylinder formed there- (b) an exhaust passage in said cylinder,

(c) piston means in said cylinder, said piston means having a shaft extending beyond one end of said cylinder for connecting a working tool thereto,

((1) a first fluid supply passage for conducting fluid pressure to one end of said cylinder,

(e) a second fluid supply passage for conducting fluid pressure to the opposite end of said cylinder,

(f) valve means slidably mounted in said cylinder and communicating said passages for alternately opening and closing communication through each of said passages,

(g) said valve means having a bore formed therein for receiving said piston, and upper and lower annular shoulders formed thereon for receiving fluid pressure to reciprocate said valve relative to said cylinder,

(h) first conduit means for conducting fluid pressure to said upper annular shoulder to move said valve means to close said first fluid passage after fluid pressure has been applied therethrough to said one end of said cylinder to prevent said piston from contacting said one end, and thereafter to open said second 10 fluid passage to communicate fluid pressure to said piston to move same for said one end, and

(i) a second conduit means for conducting fluid pressure to said lower annular shoulder to move said valve means to open said first passage and to thereafter close said second passage to reciprocate said piston and the piston shaft relative to said cylinder.

2. An impact tool comprising:

(a) a support housing having a chamber therein,

(b) fluid actuated power means adapted to reciprocate a working tool attached thereto,

(0) said power means slidably mounted in said chamber and adapted to be reciprocated therewith, said power means including:

(1) a body,

(2) a cylinder formed in said body,

(3) a piston shaft in said cylinder,

(4) pressure fluid supply passages connecting said cylinder for conducting fluid pressure thereto,

(5) exhaust ports in said cylinder for exhausting fluid pressure therefrom, and

(6) valve means associated with said exhaust ports to exhaust fluid pressure therefrom,

(d) mutfler means in said body adapted to be reciprocated therewith, and

(e) passage means for connecting said exhaust ports thereto to conduct fluid pressure from said cylinder to said mufller means to muffle the noise of fluid escaping from said power means.

3. The structure set forth in claim 2 including, alternate baffle means in said muffler means to require the exhaust fluid passing therethrough to follow an undulating course.

4. The structure set forth in claim 2 wherein said muffler means comprises:

(a) a substantially cylindrical chamber said body,

(b) alternatively disposed semicircular bafile plates in said chamber, and

(c) concentric semicircular ports in each of said semicircular baflle plates forming a substantially cylindrical passage extending axially through said chamber.

5. An impact tool comprising:

(a) a support housing having a chamber therein,

(b) fluid actuated power means adapted to reciprocate a working tool attached thereto,

(c) said power means slidably mounted in said chamber and adapted to be reciprocated therewith, said power means including:

(1) a hollow case,

(2) a body disposed in said case,

(3) a substantially cylindrical passage in said body having a piston reciprocally mounted therein,

(4) pressure fluid supply passages in said body and connecting said cylindrical passage for conducting fluid pressure thereto,

(5) exhaust ports in said body for exhausting fluid from said cylindrical passage,

(6) manifold means in said hollow case connectin-g said exhaust ports for receiving fluid escaping from said passage,

(7) muflier means in said case and connected to said manifold to muflle the noise of fluid escaping from said passage, and

(8) said hol-low case having live rubber therein surrounding said body and said manifold means and said mufller means to reduce the noise and vibration of said impact tool when in use.

6. An impact tool comprising:

(a) a support housing having a chamber therein,

(b) fluid actuated power means adapted to reciprocate a working tool attached thereto,

formed in (c) said power means slidably mounted in said chamber adapted to be reciprocated therewith, said power means including:

(1) a body,

(2) a cylinder formed in said body,

(3) a unitary piston and piston shaft in said cylinder,

(4) pressure fluid supply passages connecting said cylinder for conducting fluid pressure thereto to reciprocate said unitary piston and piston shaft therein,

(5) exhaust ports in said cylinder for exhausting fluid pressure therefrom, and

(6) valve means associated with said exhaust ports to exhaust fluid pressure therefrom,

(d) mufller means in s aid body adapted to be reciprocated therewith, and

(e) passage means for connecting said exhaust ports thereto to conduct fluid pressure from said cylinder to said muflier means to rnuflie the noise of fluid escaping from said power means.

7. An impact tool comprising:

(a) a support housing having a chamber therein;

(b) fluid actuated power means for reciprocating a 12 ('3) a piston slidably received in said body; and (4) supply means communicating pressure fluid to said cylinder for reciprocating said piston; and (c) live rubber surrounding said body for reducing noise from said body and for reducing vibration of said body on reciprocation of said piston in said cylinder, said rubber joining said body to said support housing.

References Cited UNITED STATES PATENTS 665,391 1/1901 Chapman 173-162 1,598,426 8/192-6 Ditson 173-132 2,122,517 7/1938 Curtis 181-361 2,275,102 3/1942 FitzSimmons 173-139 2,897,782 8/ 1959 Kennedy 173-126 2,983,323 6/1961 Whitney 173-139 3,181,428 5/ 1965 Volkmann 173-169 3,200,893 8/1965 Leavell 173-162 3,223,181 12/ 1965 Price 173-162 working tool attached thereto, said means including: 25 FRED RN, JR., Primary Examiner.

(1) a body; (2) a cylinder in said body;

L. P. KESSLER, Assistant Examiner. 

7. AN IMPACT TOOL COMPRISING: (A) A SUPPORT HOUSING HAVING A CHAMBER THEREIN; (B) FLUID ACTUATED POWER MEANS FOR RECIPROCATING A WORKING TOOL ATTACHED THERETO, SAID MEANS INCLUDING: (1) A BODY; (2) A CYLINDER IN SAID BODY; (3) A PISTON SLIDABLY RECEIVED IN SAID BODY; AND (4) SUPPLY MEANS COMMUNICATING PRESSURE FLUID TO SAID CYLINDER FOR RECIPROCATING SAID PISTON; AND (C) LIVE RUBBER SURROUNDING SAID BODY FOR REDUCING NOISE FROM SAID BODY AND FOR REDUCING VIBRATION OF SAID BODY ON RECIPROCATION OF SAID PISTON IN SAID CYLINDER, SAID RUBBER JOINING SAID BODY TO SAID SUPPORT HOUSING. 